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W. WILSON.

SEWING MACHINE.

APPLICATION men MAY 11. 1915.

Patented Aug. 12, 1919.

Mfiluesses: Mw@@mm- "UNIED STATES PATENT OFFICE.

WILLIAM WILSON, F BOSTON, MASSACHUSETTS, ASSIGNOR TO CAMPBELL BOSWORTH MACHINERY COMPANY, OF PORTLAND, MAINE, A CORPORATION OF MAINE.

SEWING-MACHINE.

To all whom it may concern:

Be it known that I, WILLIAM WILSON, a

- citizen of the United States, residing at Boston, in the county of Suffolk and State of Massachusetts, have invented certain new and useful Improvements in Sewing-Machines; and I do hereby declare the following to be a full, clear, and exact description of the invention, such as will enable others skilled in the art to which it appertains to make and use the same.

This invention relates to sewing machines and, more particularly, to thread cutting devices for severing the thread between the sewing mechanism and the work at the completion of the sewing operation.

The objects of the invention are to improve the construction and operation of such thread cutting devices -and to produce a thread cutting device by which the thread may be easily and conveniently severed between the sewing mechanism and the work after a seam is finished.

With these objects in view the invention consists in certain novel and improved constructions and combinations hereinafter described and particularly pointed out in the claims, the advantages of which will be obvious to one skilled in the art.

The invention will be readily understood from an inspection of the accompanying drawings illustrating the invention in its preferred form and the following detailed description thereof.

In the drawings, Figure 1 is a view in front elevation of a portion of a sewing machine with the invention applied thereto; Fig. 2 is an under side plan View of the work supporting plate and associated parts of the sewing machine detached from the machine, and Fig. 3 is a sectional view taken substantially on the line 33 of Fig. 2.

The sewing machine illustrated in the drawing is a straight hook needle wax thread lock stitch machine for sewing leather articles, the parts of which have substantially the same construction, arrangement and mode of operation as the corresponding parts of the machine illustrated in applicants application Ser. No. 621,286, filed April 15, 1911. upon which Patent No. 1,170,022, dated February 1, 1916, was granted. This machine comprises a straight hook needle indicated at 2, a looper 4 for laying the thread in the hook of the needle,

Specification of Letters Patent.

Application filed May 17, 1915.

Patented Aug. 12, 1919.

Serial No. 28,630.

a thread finger 6 and devices cotiperating with these parts to form a lock stitch seam and a presser foot 8. During the sewing operation the work is supported upon a plate 10 which is attached to the upper end of the post or housing 12, the plate having a slot 14 in which the needle and awl operate.

To form a support for the thread cutting knife the work supporting plate 10 is constructed with an extension 16 projecting from the body of the plate in the direction of feed. The thread cutting knife consists of a circular disk 18 having a peripheral knife edge and secured by means of a bolt 20 to the under side of the knife support 16, as shown particularly in Figs. 2 and 3. The knife has a diameter somewhat less than the width of the knife support and is mounted on the knife support in a position such that the marginal portion of the knife support projects beyond the knife at all points except at the operating portion thereof where the threads are presented to the knife edge. The knife support therefore forms a guard for'the knife to prevent the operator from cutting his hands upon the knife edge, and to protect the edge of the knife from being engaged by the leatherstock which is being sewn or by the buckles or other metal parts attached to the stock and thereby dulled. To enable the threads to be engaged with the knife edge the knife support 16 is formed with a thread slot 22 as shown in Fig. 2, the slot extending somewhat beyond the edge of the knife. The knife support is also formed with a thread guiding edge 24: extending at an oblique angle to the line of feed and leading to the mouth of the slot 22 to assist the operator in placing the threads in the slot. The portion 26 of the knife support 16 in front of the thread slot 22 is arranged to project slightly beyond the thread guiding edge 24 to prevent the threads from passing the thread slot 22 as they are drawn forward along the guiding edge 24.

In the operation of the thread cutting device above described after the seam is finished the work as it is removed from between the work support and the presser foot is moved in the direction of feed and manipulated to engage both the needle thread and the shuttle thread leading from the sewing mechanism to the work with the thread guiding edge, a certain amount of thread being drawn from the supplies 1n this movewill ment of the work. The work is then moved forward with the thread drawing across the guiding edge 24: until the threads are engaged by the projection 26 in front of the thread slot and thereby conducted into the thread slot where they are severed by the edge of the knife 18. The cutting point of the knife is preferably located at a distance from the sewing mechanism such that the threads are out off at the proper point to leave a suificient length of the threads projecting beyond the sewing mechanism to enable a new seam to be commenced in a certain and reliable manner with very little Waste of thread. The circular knife 18 is mounted in fixed position upon the knife support but may be adjusted angularly about the bolt 20 by which it is secured to the knife support. This manner of mounting the knife enables the knife to be adjusted so as to present a sharp portion of its edge in cutting position when the operating portion thereof opposite the thread slot has become dulled by use.

Having explained the nature and object of the invention and having specifically described the preferred embodiment thereof what is claimed is 1. A sewing machine having, in combination, stitch forming devices, a plate having a thread slot, a knife arranged with its cutting edge extending across the slot, a guide for the thread leading to the slot and a projection at one side of the slot extending beyond the line of the guide to intercept the thread as it is drawn along the guide and conduct it into the slot.

2. A sewing machine having, in combination, stitch forming devices, a plate having a thread slot a thread cutting disk mounted onthe plate with its edge extending across the slot and means for securing the disk Copies of this patent may be, obtained for five cents each, by addressing the mounted on the plate with its edge within the thread guiding edge of the plate and extending across the slot.

4:. A sewing machine having, in combination, stitch forming devices, a plate having athread slot and a sta-tionarily mounted thread cutting knife arranged with its cutting edge extending across the slot, means whereby the knife may be adjusted to present different portions of its cutting edge in cutting position relative to the slot, a guide for the thread leading to the slot and a pro jection at one side of the slot to intercept the thread and conduct it into the slot.

5; A sewing machine having, in combination, stitch forming devices, a plate having a thread slot and an angularly adjustable thread cutting disk extending across the slot, a guide for the thread leading to the slot and a projection at one side of the slot to intercept the thread and conduct it into the slot.

6. A sewing machine having in combination stitch forming devices, a supporting plate, a thread cutting disk mounted on the plate with a portion of its edge extending beyond the plate into cutting position and means for securing the disk from rotation on the plate having provision whereby the disk may be angularly adjusted to present different portions of its edge in cutting position.

WILLIAM WILSON.

Commissioner of Patents,

Washington, D. G. 

